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V689 Monocerotis, HD47432, HIP31766

V689 Monocerotis is a blue pulsating star that can be located in the constellation of Monoceros. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

HIP31766 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD47432.

V689 Monocerotis has alternative name(s), V689 Mon.

Location of V689 Monocerotis

The location of the star in the galaxy is determined by the Right Ascension (R.A.) and Declination (Dec.), these are equivalent to the Longitude and Latitude on the Earth. The Right Ascension is how far expressed in time (hh:mm:ss) the star is along the celestial equator. If the R.A. is positive then its eastwards. The Declination is how far north or south the star is compared to the celestial equator and is expressed in degrees. For V689 Monocerotis, the location is 06h 38m 38.19 and +01d 36` 48.7 .

Proper Motion of V689 Monocerotis

All stars like planets orbit round a central spot, in the case of planets, its the central star such as the Sun. In the case of a star, its the galactic centre. The constellations that we see today will be different than they were 50,000 years ago or 50,000 years from now. Proper Motion details the movements of these stars and are measured in milliarcseconds. The star is moving -0.83 ± 0.30 miliarcseconds/year towards the north and -0.34 ± 0.54 miliarcseconds/year east if we saw them in the horizon. The Radial Velocity, that is the speed at which the star is moving away/towards us is 60.10000 km/s with an error of about 1.50 km/s .

Physical Properties (Colour, Temperature, Radius) of V689 Monocerotis

V689 Monocerotis has a spectral type of O9.5II. This means the star is a blue star. The star has a B-V Colour Index of 0.08 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 8,721 Kelvin.

V689 Monocerotis Radius has been calculated as being 24.20 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 16,838,102.66.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 15.48. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

V689 Monocerotis Apparent and Absolute Magnitudes

V689 Monocerotis has an apparent magnitude of 6.23 which is how bright we see the star from Earth. Apparent Magnitude is also known as Visual Magnitude. If you used the 1997 Parallax value, you would get an absolute magnitude of -3.86 If you used the 2007 Parallax value, you would get an absolute magnitude of -2.89. Magnitude, whether it be apparent/visual or absolute magnitude is measured by a number, the smaller the number, the brighter the Star is. Our own Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.

Distance to V689 Monocerotis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 0.96 which gave the calculated distance to V689 Monocerotis as 3397.53 light years away from Earth or 1041.67 parsecs. It would take a spaceship travelling at the speed of light, 3397.53 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.

In 2007, Hipparcos data was revised with a new parallax of 1.50 which put V689 Monocerotis at a distance of 2174.42 light years or 666.67 parsecs. It should not be taken as though the star is moving closer or further away from us. It is purely that the distance was recalculated.

Variable Type of V689 Monocerotis

The star is a pulsating Alpha Cygnus variable type which means that its size changes over time. The Variable Type is usually named after the first star of that type to be spotted. V689 Monocerotis brightness ranges from a magnitude of 6.287 to a magnitude of 6.235 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.0 days (variability).

Source of Information

The source of the information if it has a Hip I.D. is from Simbad, the Hipparcos data library based at the University at Strasbourg, France. Hipparcos was a E.S.A. satellite operation launched in 1989 for four years. The items in red are values that I've calculated so they could well be wrong. Information regarding Metallicity and/or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

V689 Monocerotis Facts

Alternative Names

Traditional/Proper NameV689 Monocerotis
Short NameV689 Mon
Hipparcos Library I.D.31766
Bonner DurchmusterungBD+01 1443
Henry Draper Designation47432

Visual Facts

Star Type star
Absolute Magnitude-3.86 / -2.89
Visual / Apparent Magnitude6.23
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)06h 38m 38.19
Declination (Dec.)+01d 36` 48.7
Galactic Latitude-2.11 degrees
Galactic Longitude210.03 degrees
1997 Distance from Earth0.96 Parallax (milliarcseconds)
 3397.53 Light Years
 1041.67 Parsecs
2007 Revised Distance from Earth1.50 Parallax (milliarcseconds)
 2174.42 Light Years
 666.67 Parsecs
Proper Motion Dec.-0.83 ± 0.30 milliarcseconds/year
Proper Motion RA.-0.34 ± 0.54 milliarcseconds/year
B-V Index0.08
Radial Velocity60.10 ± 1.50 km/s
Spectral TypeO9.5II
Colour(O) blue

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeAlpha Cygnus
Mean Variability Period in Days0.045
Variable Magnitude Range (Brighter - Dimmer)6.235 - 6.287

Estimated Facts

Calculated Effective Temperature8,721 Kelvin

Sources and Links

SIMBAD SourceLink

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